Prudence Honeysett is a wealthy, aging widow who's also quite done with the world. A hopeless curmudgeon, she withdraws from Victorian society by purchasing an old priory reputed to be haunted, convinced that her desire for peace and quiet would be perfectly met regardless. Fortune, however, has different plans for her, her hapless servants, and her trio of monstrous cats.

The sudden appearance of a heartbroken nephew at her doorstep stirs the ghostly waters even more after Frederick confesses to being a medium, and before Prudence knows it, the long-dead residents of St. Grimald priory emerge from the shadows. And they all come with garbled warnings of a murdered girl and the door to the underworld on its way to being torn down.

Through a collection of humorous journal entries and letters, the supernatural misadventures of Prudence and Frederick unfold-filled with sordid family drama, swoony romantic entanglements, dodgy attempts at questionable magic, and restless ghosts a-plenty.